Staff Member

It's likely a bounce message from a failed delivery that was sent out when the account was spamming. I recommend monitoring the /var/log/exim_mainlog and your mail queue to make sure additional messages are not sending out from that account. The following document is also helpful:

Thank you very much for your advise. I will way a little and see if it does stop. I also look at the documentation again. I think the attack happen through my testing site so hopefully the measure I took will be enough.

I was also wondering where I could find a good course to learn how to use WHM/cPanel. Would you have a recommendation?